Like commit 42d5e37654e4 ("audit: filter PATH records keyed on
filesystem magic") that addresses
https://github.com/linux-audit/audit-kernel/issues/8
Any user or remote filesystem could become unavailable and effectively
block on a forced unmount.
-a always,exit -S umount2 -F key=umount2
Provide a method to ignore these user and remote filesystems to prevent
them from being impossible to unmount.
Extend the "AUDIT_FILTER_FS" filter that uses the field type
AUDIT_FSTYPE keying off the filesystem 4-octet hexadecimal magic
identifier to filter specific filesystems to cover audit_inode() to address
this blockage.
An example rule would look like:
-a never,filesystem -F fstype=0x517B -F key=ignore_smb
-a never,filesystem -F fstype=0x6969 -F key=ignore_nfs
Arguably the better way to address this issue is to disable auditing
processes that touch removable filesystems.
Note: refactor __audit_inode_child() to remove two levels of if
indentation.
Please see the github issue tracker
https://github.com/linux-audit/audit-kernel/issues/100
Signed-off-by: Richard Guy Briggs <r...@redhat.com>
---
kernel/auditsc.c | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b585ceb2f7a2..3d05d5fc6240 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1763,10 +1763,31 @@ void __audit_inode(struct filename *name, const struct
dentry *dentry,
struct inode *inode = d_backing_inode(dentry);
struct audit_names *n;
bool parent = flags & AUDIT_INODE_PARENT;
+ struct audit_entry *e;
+ struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS];
+ int i;
if (!context->in_syscall)
return;
+ rcu_read_lock();
+ if (!list_empty(list)) {
+ list_for_each_entry_rcu(e, list, list) {
+ for (i = 0; i < e->rule.field_count; i++) {
+ struct audit_field *f = &e->rule.fields[i];
+
+ if (f->type == AUDIT_FSTYPE
+ && audit_comparator(inode->i_sb->s_magic,
+ f->op, f->val)
+ && e->rule.action == AUDIT_NEVER) {
+ rcu_read_unlock();
+ return;
+ }
+ }
+ }
+ }
+ rcu_read_unlock();
+
if (!name)
goto out_alloc;
@@ -1875,14 +1896,12 @@ void __audit_inode_child(struct inode *parent,
for (i = 0; i < e->rule.field_count; i++) {
struct audit_field *f = &e->rule.fields[i];
- if (f->type == AUDIT_FSTYPE) {
- if
(audit_comparator(parent->i_sb->s_magic,
- f->op, f->val)) {
- if (e->rule.action ==
AUDIT_NEVER) {
- rcu_read_unlock();
- return;
- }
- }
+ if (f->type == AUDIT_FSTYPE
+ && audit_comparator(parent->i_sb->s_magic,
+ f->op, f->val)
+ && e->rule.action == AUDIT_NEVER) {
+ rcu_read_unlock();
+ return;
}
}
}
--
1.8.3.1
